What To Do If You Put The Wrong Fuel In Your Car

It is estimated that a motorist puts the wrong fuel in their vehicle every three and a half minutes. All it takes is a momentary lapse in concentration and all of a sudden, you've put petrol in your diesel or diesel in your petrol.

Misfuelling your car can be a costly mistake, but there are actions you can take to minimise the amount you have to pay.

WHAT DO YOU DO WHEN YOU PUT THE WRONG FUEL IN YOUR CAR?

The number one rule is to not start the engine or even put the key in the ignition. Switching the engine on will draw the fuel up into the system, whereas, if you can keep it contained in the fuel tank, the damage will be minimised.

You should then tell the fuel station attendant about your mistake. Although this is embarrassing, 150,000 people do it every year, so it's highly likely that they've encountered this situation before.

Try to get some help from someone working at the fuel station to push your car to a safe location - most will have parking spaces that you can use.

The last thing you need to do is call your breakdown cover. Most of the big companies (e.g. AA or RAC) have dedicated misfuel departments. If your breakdown cover doesn't, there are specialist companies available that you can contact.

As long as you don't turn the key in the ignition, it's likely that it will only cost around £200 to drain your fuel tank, plus the cost of two tanks of fuel.

WHAT HAPPENS IF YOU DON'T REALISE YOUR MISFUELING MISTAKE?

If you don't realise that you've put the wrong fuel in your car and attempt to drive away, the damage will be more extensive which will be reflected in the price you have to pay to fix any affected parts.

Symptoms of misfuelling include: 'lumpy' or erratic acceleration, misfiring and excessive smoke coming from the exhaust. If you experience any of these symptoms, it's always best to call your breakdown service, rather than trying to persevere.

The longer the wrong fuel is pumping around your car's internal system, the more damage it will do. You could end up paying for new fuel pumps, injectors, pipes, filters, fuel tank - or even a whole new replacement engine, which could cost thousands.

WHAT HAPPENS WHEN DIESEL IS PUT IN PETROL CARS?

This is a less common mistake because diesel pump nozzles tend to be larger than most petrol fuel necks, but it does still happen. It's also much less disastrous when it happens.

Diesel and petrol are ignited in two completely different ways: diesel has to be compressed to ignite, whereas petrol is ignited by a spark generated by the spark plugs.

The most common result of diesel being put into a petrol engine is that the spark plugs and fuel system get clogged up, so the engine won't start anyway.

WHAT HAPPENS WHEN PETROL IS PUT IN DIESEL CARS?

Diesel acts as a lubricant, helping the fuel pump to do its job. However, petrol acts in the opposite way and has a solvent effect, which reduces lubrication and damages the pump.

Without the necessary lubrication, there will be increased friction between metal parts causing extensive damage to the fuel lines and pumps.

In order to achieve their impressive mpg figures and minimise emissions, modern diesel engines employ lots of sophisticated technology, including expensive high-pressure fuel pumps and common rail injectors with very fine tolerances.

Replacing these parts could potentially cost you thousands of pounds. It's important to note, that driving a very short distance on the wrong fuel is not guaranteed to cause problems as severe as this, but it is very possible.

CAN I REDUCE THE RISK OF MISFUELLING?

Misfuelling only takes a moment’s distraction, so pay attention if you’ve bought a new car or are using a different one. You’re also more likely to misfuel in an unfamiliar petrol station, or if you’ve started using a different fuel brand.

When fuelling up, don’t allow yourself to be distracted by other people including your passengers. Finally, never assume hose colours are the same, as they can be different at various petrol stations or change without warning.

Misfuelling is a costly mistake that is easily avoided. Simply pay the same level of attention at the petrol station that you do when you’re on the road, and if you do misfuel, don’t let the problem escalate.